code: def test_return_dataframe_merge_is_None(returns_frame_1):
      """
      Test that the dataframe returned when `merge_frame` is None
      is the result of the text processing, and is not merged to
      the original dataframe.
      """
  
      expected_output = returns_frame_1["ticker"].str.split(
          " ", expand=True
      )
      result = returns_frame_1.process_text(
          column_name="ticker",
          string_function="split",
          expand=True,
          pat=" ",
      )
      assert_frame_equal(result, expected_output)
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 21 for calling a global function with example usage: test_return_dataframe_merge_is_None(returns_frame_1) without return types